There aren't actually any rulings about how the player must perform the shuffle, meaning that they could theoretically conceal their shuffling completely and turn your opponent's blocking into a complete guessing game as opposed to trying to follow the shuffle around which might have been the intention of the card
You just shove a bunch of tokens in to attack, and then exile them during End of Combat
No two are really even remotely the same, and this article takes a look at a little bit of everything
While a single use ability is a little limited, even one as good as Headliner Scarletts, is a bit weak, she comes with a second one to balance her out
The double black casting cost is certainly a hindrance, but Graveyard Marshal is a quality two-drop thats an amazing draw in the late game when you have access to tons of mana, which is incredibly valuable